Medium discharging mechanism and image forming apparatus that employs the medium discharging mechanism

ABSTRACT

A medium discharging mechanism includes a first roller, a second roller, and a resiliently deformable member. The second roller is in pressure contact with the first roller to form a nip between the first roller and the second roller. The resiliently deformable member is formed of a resiliently deformable material and is rotatable about a rotating shaft of one of the second roller. The resilient member has a larger diameter than the second roller. The resilient member deforms at the nip such that a surface of the resilient ring is flush with the nip.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a medium-discharging mechanism and animage-forming apparatus that employs the medium-discharging mechanism.

2. Description of the Related Art

A conventional image-forming apparatus such as a printer, copyingmachine, facsimile machine, and plotter is provided with amedium-discharging mechanism for discharging a printed medium. Themedium-discharging mechanism includes a discharge roller and a pressureroller in pressure contact with the discharge roller. When the dischargeroller is rotated in one direction, the pressure roller is driven torotate in an opposite direction to the discharge roller such that theprinted medium is pulled in therebetween. The printed medium is heldbetween the discharge roller and pressure roller in a sandwichedrelation, and is advanced to a stacker.

Once a rear end of the medium has passed through a nip formed betweenthe discharge roller and pressure roller, the discharge roller andpressure roller no longer cause the medium to advance. Thus, the rearend of the medium tends to remain on the pressure roller, blocking thedischarging path of the medium. When the rear end of the medium blocksthe discharging path, the preceding page of the medium is pushed by thefollowing page to drop from the stacker or resulting in a paper jam.

In order to solve this problem, a vane-like member is disposed at bothlongitudinal ends of the pressure roller. The vane-like member is formedof a soft material such as rubber or sponge. The vane-like memberrotates together with the pressure roller to advance the medium towardstacker.

The vane-like member rotates continuously to hit the medium periodicallyirrespective of the position of the medium relative to the pressureroller. This gives rise to not only annoying noise but also wear-out ofand damage to the vane-like member, thereby decreasing durability of themedium-discharging mechanism.

One conventional medium-discharging mechanism is constructed as follows:A driven gear is provided to a shaft that supports the vane-like member.A drive gear is provided which rotates in mesh with the driven gear onthe shaft to drive the vane-like member in rotation. When the medium isbeing transported through the nip between the pressure roller and thedischarge roller, the drive gear is not in mesh with the driven gear.After the rear end of the medium has passed the nip, the drive gearmoves into a meshing engagement with the driven gear to drive thevane-like member into rotation. In other words, the drive gear is inmesh with the driven gear only after the medium has passed the nip.

With the aforementioned conventional medium-discharging mechanism, thevane-like member is rotated intermittently. This requires gears to havespecial shapes, increasing the number of components and complexity ofthe medium-discharging mechanism. The resulting image-forming apparatusis of large overall size and highly costly.

SUMMARY OF THE INVENTION

An object of the invention is to solve the aforementioned drawbacks.

Another object of the invention is to provide a medium-dischargingmechanism and image-forming apparatus that do not emit annoying noise,improves durability of the medium-discharging mechanism, and is suitablefor miniaturizing the device, and reducing the manufacturing cost.

A medium discharging mechanism includes a first roller, a second roller,and a resilient member. The second roller is in pressure contact withthe first roller to form a nip between the first roller and the secondroller. The resilient member is formed of a resiliently deformablematerial and is rotatable about a rotating shaft of one of the secondroller. The resilient member has a larger diameter than the secondroller.

The resiliently deformable member deforms is in the shape of a ringfitted in an annular groove formed in a circumferential surface of thesecond roller.

The resiliently deformable member deforms at a nip formed between thefirst roller and the second roller.

The resiliently deformable member deforms at the nip such that a surfaceof the resilient ring is flush with the nip.

The resiliently deformable member is made of a high friction material.

The resiliently deformable member includes projections and recessesaligned alternately on a circumferential surface of the resilientlydeformable member.

The resiliently deformable member has projections and recesses on itscircumferential outer surface such that the projections and recessesform a wavy surface.

The resiliently deformable member is mounted outside of an area in whichthe first roller and the second roller are in contact with each other.

The resiliently deformable member is one of at least two resilientlydeformable members mounted on longitudinal end portions of the secondroller.

The second roller is one of a plurality of second rollers that rotateabout the rotating shaft, wherein the resiliently deformable member isdisposed such that the resiliently deformable member is sandwichedbetween adjacent second rollers.

The medium discharging mechanism further includes a weight that isfreely rotatable on the rotating shaft and hangs down from the rotatingshaft. When the medium is pulled in between the first roller and thesecond roller, the leading end of the medium pushes the weight out ofthe way so that the weight presses on a surface of the medium until atrailing end of the medium leaves the nip.

The first roller and second roller form a nip between them such that thenip lies in a plane at an angle with a transport path in which themedium advances toward the nip.

The first roller and the second roller are positioned so that the firstroller is on one side of the transport path and the second roller is onthe other side of the transport path, the first roller being upstream ofthe second roller.

An image forming apparatus incorporates the aforementioned mediumdischarging mechanism.

Further scope of applicability of the present invention will becomeapparent from the detailed description given hereinafter. However, itshould be understood that the detailed description and specificexamples, while indicating preferred embodiments of the invention, aregiven by way of illustration only, since various changes andmodifications within the spirit and scope of the invention will becomeapparent to those skilled in the art from this detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from thedetailed description given hereinbelow and the accompanying drawingswhich are given by way of illustration only, and thus are not limitingthe present invention, and wherein:

FIG. 1 is a schematic view of a printer according to a first embodiment;

FIG. 2 is a perspective view of a medium discharging mechanism accordingto the first embodiment;

FIG. 3 is a front view of a pertinent portion of the medium dischargingmechanism according to the first embodiment;

FIG. 4A is a perspective view of the medium discharging mechanism;

FIG. 4B is a side view of a pertinent portion of the medium dischargingmechanism;

FIG. 5 is an exploded perspective view of a pressure roller;

FIG. 6 illustrates the operation of the medium discharging mechanism;

FIG. 7 illustrates the operation of a medium discharging mechanismaccording to a second embodiment;

FIG. 8 is an exploded perspective view of a pressure roller according toa third embodiment;

FIG. 9 is a front view illustrating a medium discharging mechanismaccording to the third embodiment;

FIG. 10 is an exploded perspective view of a pressure roller accordingto a fourth embodiment; and

FIG. 11 is a front view of a pertinent portion of a medium dischargingmechanism according to the fourth embodiment;

FIG. 12 is a perspective view illustrating a medium-dischargingmechanism according to a fifth embodiment;

FIG. 13 is a side view of a medium-discharging mechanism according tothe fifth embodiment before the paper is pulled in between the dischargeroller and the pressure roller;

FIG. 14 is a side view illustrating the positional relation betweenpaper and a weight member; and

FIG. 15 is a perspective view illustrating the positional relationbetween the paper and the weight member.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will be described in detail with reference to theaccompanying drawings. The image forming apparatus according to theinvention will be described in terms of a printer.

First Embodiment

FIG. 1 is a schematic view of a printer according to a first embodiment.

FIG. 2 is a perspective view of a medium-discharging mechanism accordingto the first embodiment.

Referring to FIG. 1, a printer 11 includes image forming sections 12BK,12Y, 12M, and 12C for black, yellow, magenta, and cyan images,respectively. Each of the image-forming sections includes aphotoconductive drum 13 that bears an image on it. The image-formingsection further includes a charging roller 14 that charges the surfaceof the photoconductive drum 13, a developing unit 16, and a cleaningunit 18, which are disposed to surround the photoconductive drum 13.

An LED head 15 is disposed over the photoconductive drum 13. A transferunit is disposed under the photoconductive drum 13. The transfer unitincludes a transport belt 19 that runs in a direction in which theimage-forming sections are aligned, a drive roller 21 that drives thetransport belt 19 to run, a driven roller 22 that is driven in rotationwhen a drive roller 21, and a transfer roller 17 that opposes thephotoconductive drum 13 with the medium sandwiched between the transferroller 17 and photoconductive drum 13.

The charging roller 14 uniformly charges the surface of thephotoconductive drum 13. The LED head 15 illuminates the charged surfaceof the photoconductive drum 13 to form an electrostatic latent image inaccordance with printed data. The developing unit holds toner thereinand supplies the toner to the electrostatic latent image formed on thephotoconductive drum 13, thereby developing the electrostatic latentimage into a toner image.

Paper 20 is fed from a paper-feeding mechanism 23 and is then attractedto the transport belt 19. The transport belt 19 attracts the paper 20,and advances through the image-forming sections 12BK, 12Y, 12M, and 12Csuch that toner images of the respective colors are transferred onto thepaper 20 in registration, thereby forming a full color toner image.

A paper-feeding mechanism 23 is located at an upstream end in adirection of travel of the paper 20 (i.e., to the right of the drivenroller 22). A paper cassette 24 holds a stack of the paper 20. A feedroller 25 separates the top page of the stack of the paper 20 and feedsthe top page onto a transport path for the paper 20. A sensor 26 detectsthe passage of the paper 20. A transport roller 27 opposes the drivenroller 22 such that the transport belt 19 is sandwiched between thetransport roller 27 and the driven roller 22.

A fixing unit 28 is disposed to the left of the drive roller 21 (i.e.,downstream side in a direction of travel of the paper 20). The fixingunit 28 includes a heat roller 29, and a pressure roller 30 in pressurecontact with the heat roller 29, and fuses the toner image into apermanent color image.

Referring to FIG. 2, a medium-discharging mechanism is disposed at adownstream of the fixing unit 28. The medium-discharging mechanismincludes a frame 37, three discharge rollers 31, three pressure rollers32, a resilient ring 36A, and a stacker 50. The discharge roller 31 isrotatably supported on the frame 37. The pressure roller 32 is alsorotatably supported on the frame 37, and is in pressure contact with thedischarge roller 31. The resilient ring 36A is resiliently deformableand is mounted to the pressure roller 32 and pushes the paper 20 towardthe stacker 50.

The shaft 31 a of the discharge rollers 31 is rotatably supported on theframe 37, and extends through three discharge rollers 31 so that thedischarge rollers rotate at three separate locations on the shaft 31 a.A discharge guide 38 is formed at a downstream end portion of the frame37. The three pressure rollers 32 are rotatably supported on thedischarge guide 38 and are disposed to oppose the three dischargerollers 31.

The shaft 31 a has a gear 40 mounted at its one end portion. The gear 40is coupled to a motor gear, not shown, mounted on an output shaft of amotor 49 through idle gears 41-47. When the motor 49 rotates, the shaft31 a is rotated.

The discharge rollers 31 and pressure rollers 32 of themedium-discharging mechanism will be described.

FIG. 3 is a front view of a pertinent portion of the medium-dischargingmechanism according to the first embodiment. FIG. 5 is an explodedperspective view of the pressure roller 32. FIG. 6 illustrates theoperation of the medium-discharging mechanism.

Referring to FIG. 3, the discharge roller 31 is formed of a resilientmaterial such as silicone rubber, or EPDM rubber. The pressure roller 32is molded from a resin and has a cylindrical inner space. The dischargeroller 31 and pressure roller 32 are in pressure contact with each otherto form a nip therebetween. The shaft 33 is supported on the dischargeguide 38 and extends through the pressure rollers 32 so that thepressure rollers 32 are free to rotate on the shaft 33.

FIG. 4A is a perspective view of the medium-discharging mechanism. FIG.4B is a side view of a pertinent portion of the medium-dischargingmechanism.

The discharge guide 38 includes a spring assembly 35 mounted to asupporting member, not shown. The spring assembly 35 includes supports35 a and 35 b that support the shaft 33, and flat springs 35 c and 35 dthat urge the pressure rollers 32 against the discharge rollers 31.

Referring to FIG. 5, the pressure roller 32 is formed with acircumferential groove 32 a at a laterally centered position. Theresilient ring 36A is detachably received in the groove 32 a, so thatthe resilient ring 36A is in coaxial alignment with a shaft of thepressure roller 32. The resilient ring 36A is generally ring-shaped andis made of a soft resiliently deformable material such as urethane foam.The resilient ring 36A has an inner diameter smaller than the diameterof the bottom of the groove 32 a and has a larger outer diameter thanthe pressure roller 32. The resilient ring 36A is assembled to fit intothe groove 32 a of the pressure roller 32, so that the outer surface ofthe resilient ring 36A projects radially outwardly from the groove 32 a.Shortly after the paper 20 leaves the nip formed between the dischargeroller 31 and pressure roller 32, the outer surface of the resilientring 36A pushes the rear end of the paper 20 to advance the paper 20toward the stacker 50.

The discharge roller 31 and pressure roller 32 are in pressure contactwith each other to form a nip between them. The outwardly projectingportion of the resilient ring 36A is pushed back or collapsed so thatthe outer surface of the resilient ring 36A is flush with the nip area.Therefore, the resilient ring 36A is not obstacle in advancing the paper20 through the nip.

Referring to FIG. 6, in order to ensure that the paper 20 enters a nipformed between the discharge roller 31 and the resilient ring 36Awithout difficulty, the paper 20 is fed in a direction B tangent to acircumferential surface of the discharge roller 31 at which the nip isformed. The discharge roller 31 and pressure roller 32 oppose to eachother so that the discharge roller 31 is on one side of the transportpath 37 of the paper 20 and the pressure roller 32 is on the other sideof the transport path 37 and the discharge roller 31 is slightlyupstream of the pressure roller 32. Thus, the nip lies in a plane at anangle with a direction B in which the paper 20 is advanced.

The operation of the medium-discharge mechanism of the aforementionedconfiguration will be described.

When the printer 11 (FIG. 1) receives print data from a host apparatussuch as a host computer or a controller, not shown, extracts image datafor the respective colors, and feeds the image data to the correspondingimage-forming sections. For example, image data for black is sent to theLED head 15 of the image-forming section 12BK. The LED head 15illuminates the surface of the photoconductive drum 13, charged by thecharging roller 14, thereby forming an electrostatic latent image forblack on the photoconductive drum 13. Then, the developing unit 16develops the electrostatic latent image for black into a black tonerimage.

The paper 20 is fed by the feed roller 25 and is detected by the sensor26. The transport belt 19 transports the paper 20 in timed relation withthe image formation performed at the image forming section 12BK. Thetransfer roller 17 transfers the black toner image from thephotoconductive drum 13 onto the paper 20.

The transport belt 19 further advances, with the paper 20 attracted toit, to the image forming section 12Y for yellow image. The LED head 15illuminates the surface of the photoconductive drum 13Y charged by thecharging roller 14, thereby forming an electrostatic latent image foryellow on the photoconductive drum 13Y. Then, the developing unit 16develops the electrostatic latent image for yellow into a yellow tonerimage. The transfer roller 17 transfers the yellow toner image from thephotoconductive drum 13Y onto the paper 20.

Likewise, toner images of magenta and cyan are formed in the imageforming sections 12M and 12C, respectively. Then, the developing units16 develop the electrostatic latent images for magenta and cyan intomagenta and cyan toner images, respectively. Then, the transfer rollers17 transfer the magenta and cyan toner images from the photoconductivedrums 13M and 13C, respectively, onto the paper 20 in sequence.

When a printing operation is initiated, the motor 49 (FIG. 2) drives thedischarge roller 31 in a forward direction and the pressure roller 32 inthe opposite direction to the discharge roller 31. At the same time, theresilient ring 36A is driven to rotate in the same direction as thepressure roller 32.

At this moment, as shown in FIG. 6, the resilient ring 36A is pushedback at all times by the discharge roller 31 to ensure that the paper 20enters the nip between the discharge roller and the pressure roller 32.The resilient ring 36A regains its original shape after it has passedthrough the nip.

Thus, when the rear end of the paper 20 advances past the nip by thedischarge roller 31 and the pressure roller 32, the resilient ring 36Amoves into contact engagement with the rear end portion of the paper 20,and then pushes the rear end of the paper 20 onto the stacker 50. Thiscompletes a medium discharging operation. The resilient ring 36A is aresiliently, deformable body and has a high friction resistance on itssurface. The high friction resistance is advantageous in pushing therear end of the paper 20.

In the embodiment, the combination of the resilient ring 36A with thepressure roller 32 prevents the paper 20 from being hit periodically bya surrounding mechanical member so that no annoying noise is produced.The resilient ring 36A is in contact with the discharge roller 31 at alltimes, so that the resilient ring 36A will not wear out or be damaged.This ensures the durability of the discharge roller 31.

The resilient ring 36A is rotated continuously during the mediumdischarging operation. The continuous rotation of the resilient ring 31eliminates the need for a gear(s) of a special shape, and thereforereduces the number of components, implements the small overall size ofthe printer 11, and reduces the manufacturing cost of the printer.

The resilient ring 36A has an inner diameter smaller than the diameterof the groove 32 a, which allows the resilient ring 36A to be securelymounted on and dismounted from the pressure roller 32. This facilitatesreplacement of the resilient ring 36A.

Because the resilient ring 36A is pushed back at the nip between theresilient ring 36A and discharge roller 31, even when the paper 20 has asmall thickness, no load is exerted on the paper 20 so that the paper 20may be advanced smoothly.

Second Embodiment

FIG. 7 illustrates the operation of a medium-discharging mechanismaccording to a second embodiment.

FIG. 8 is an exploded perspective view of a pressure roller of themedium-discharging mechanism.

A resilient ring 36B according to the second embodiment has projectionsand recesses on its circumferential outer surface such that theprojections and recesses form a wavy surface. The elements similar tothose of the first embodiment have been given the same referencenumerals and their description is omitted.

Referring to FIG. 7, the resilient ring 36B is formed of a resilientlydeformable material such as urethane foam and has projectionsalternating with recesses to form a wave-shaped outer surface in acircumferential direction of the resilient ring 36B. When the outersurface of the resilient ring 36B enters the nip between the dischargeroller 31 and the resilient ring 36B, the resilient ring 36B isresiliently pushed back or collapsed, and then regains its originalshape when it appears at the exit side of the nip, i.e., a downstreamside of the nip with respect to the direction in which the paper 20 istransported.

The projections and recesses that form a wave along the outer surface ofthe resilient ring 36B improve the ability of the resilient ring 36B topush the rear end of the paper 20.

Third Embodiment

In the first and second embodiments, the pressure roller 32 is formedwith a groove 32 a (FIG. 5) therein to which the resilient ring 36A or36B is fitted. A third embodiment differs from the first and secondembodiments in that the pressure roller 32 is divided into two rollersegments and a resilient disc 36C is assembled between the rollersegments. Elements similar to those in the first and second embodimentshave been given the same reference numerals and the description isomitted.

FIG. 9 is a front view illustrating a medium-discharging mechanismaccording to the third embodiment.

Referring to FIG. 9, a pressure roller 32 includes a roller segment 32 aand a roller segment 32 b. The resilient disc 36C is resilientlydeformable and is sandwiched between the roller segments 32 a and 32 b.A shaft 33 extends through the roller segments 32 a and 32 b. The thirdembodiment eliminates the need for making a groove in the shaft 33, andthus provides an easy-to-make mechanism.

The discharge roller 31 and pressure roller 32 are in pressure contactwith each other to form a nip between them. The outwardly projectingportion of the resilient disc 36C is pushed back or collapsed so thatthe outer surface of the resilient disc 36C is flush with the nip area.Therefore, the resilient disc 36C is not obstacle in advancing the paper20 through the nip.

Fourth Embodiment

FIG. 10 is an exploded perspective view of a pressure roller accordingto a fourth embodiment. FIG. 11 is a front view of a pertinent portionof a medium discharging mechanism according to the fourth embodiment.Elements similar to those in the first and second embodiments have beengiven the same reference numerals and their description is omitted.

Referring to FIG. 10, a pressure roller 52 has a larger length than adischarge roller 31, and laterally centered with respect to thedischarge roller 31 such that the longitudinal end portions of thepressure roller 52 extend further than the discharge roller 31. Thepressure roller 52 is formed with grooves 52 a and 52 b such that thedischarge roller 31 is between the grooves 52 a and 52 b. Resilientrings 53 a and 53 b fit into the grooves 52 a and 52 b, respectively.The resilient rings 53 a and 53 b are generally ring-shaped and are madeof a soft resilient material such as urethane foam. The resilient rings53 a and 53 b have an inner diameter larger than that of the bottoms ofthe grooves 52 a and 52 b, and an outer diameter than that of thepressure roller 52.

Because the resilient rings 53 a and 53 b are not in contact with thedischarge roller 31, the resilient rings 53 a and 53 b are not pushedback at all times and therefore maintains their original shape.

The paper 20 is pulled in between the discharge roller 31 and thepressure roller 32, and is advanced to a stacker. Shortly after the rearend of the paper 20 leaves the nip between the discharge roller 31 andthe pressure roller 32, the resilient rings 53 a and 53 b push the rearend of the paper 20 to the stacker. This completes a medium dischargingoperation.

The resilient rings 53 a and 53 b project radially outwardly of thecircumferential surface of the pressure roller 52, and causes the paper20 to flex slightly. This makes the paper 20 slightly rigid in itsentirety and is advantageous in transporting the paper 20 in a stablemanner.

While the first to fourth embodiments have been described in terms ofthe resilient rings 36A-36C, 53 a, 53 b assembled to the pressurerollers 32 and 52, the resilient rings 36 A-36C, 53 a, 53 b may also beassembled to the discharge roller 31 or to both discharge roller 31 andpressure roller 32.

Fifth Embodiment

When the trailing end of paper 20 leaves a medium discharging mechanism,the trailing end tends to be raised from the resilient rings of thefirst to fourth embodiments. If the paper 20 is soft, then the paper isattracted to a stacker 50 by the Coulomb force. Therefore, the resilientrings alone cannot apply a force to the paper 20 to push the paper 20away from a medium-discharging mechanism.

FIG. 12 is a perspective view illustrating a medium-dischargingmechanism according to a fifth embodiment.

Referring to FIG. 12, three discharge rollers 31 are mounted at threeseparated locations on a shaft 31 a. Three pressure rollers 32 are inpressure contact with corresponding discharge rollers 31. A weightmember 39 is rotatably mounted on the shaft 31 a between adjacentdischarge rollers 31, and hangs downward due to its own weight, andrests on a shaft 32 c of the pressure rollers 32 (FIG. 13). The paper 20advances in a direction shown by arrow A.

FIG. 13 is a side view of a medium-discharging mechanism according to afifth embodiment before the paper 20 is pulled in between the dischargeroller 31 and the pressure roller 32.

When the paper 20 advances in the A direction, the leading end of thepaper 20 pushes the weight member 39 and causes the weight member 39 topivot in a direction shown by arrow B against the weight of the weightmember 39.

FIG. 14 is a side view illustrating the positional relation between thepaper 20 and the weight member 39.

FIG. 15 is a perspective view illustrating the positional relationbetween the paper 20 and the weight member 39 when the trailing end ofthe paper 20 leaves the medium discharging mechanism.

When the trailing end of the paper 20 leaves the medium dischargingmechanism, the weight 39 is resting on the surface of the paper 20 suchthat the weight 39 exerts its own weight on the paper 20 in a directionshown by arrow C. The weight 39 presses the trailing end portion of thepaper 20 on the resilient rings, allowing the resilient ring 36A to pushreliably without idle rotation.

The invention being thus described, it will be obvious that the same maybe varied in many ways. Such variations are not to be regarded as adeparture from the spirit and scope of the invention, and all suchmodifications as would be obvious to one skilled in the art intended tobe included within the scope of the following claims.

1. A medium-discharging mechanism comprising: a first roller; a secondroller in pressure contact with said first roller such that a medium ispulled in between said first roller and said second roller; aresiliently deformable member rotatable about a rotating shaft of saidsecond roller, said resiliently deformable member having a larger outerdiameter than said second roller.
 2. The medium discharging mechanismaccording to claim 1, wherein said resiliently deformable member deformsis in the shape of a ring fitted in an annular groove formed in acircumferential surface of said second roller.
 3. The medium dischargingmechanism according to claim 2, wherein said resiliently deformablemember deforms at a nip formed between said first roller and the secondroller.
 4. The medium discharging mechanism according to claim 3,wherein said resiliently deformable member deforms such that a surfaceof the resilient ring is flush with the nip.
 5. An image formingapparatus incorporating said medium discharging mechanism according toclaim
 2. 6. The medium discharging mechanism according to claim 1,wherein said resiliently deformable member is made of a high frictionmaterial.
 7. An image forming apparatus incorporating said mediumdischarging mechanism according to claim
 6. 8. The medium dischargingmechanism according to claim 1, wherein said resiliently deformablemember includes projections and recesses aligned alternately on acircumferential surface of said resiliently deformable member.
 9. Themedium discharging mechanism according to claim 1, wherein saidresiliently deformable member has projections and recesses on itscircumferential outer surface such that the projections and recessesform a wavy surface.
 10. The medium discharging mechanism according toclaim 1, wherein said resiliently deformable member is mounted outsideof an area in which said first roller and said second roller are incontact with each other.
 11. The medium discharging mechanism accordingto claim 1, wherein said resiliently deformable member is one of atleast two resiliently deformable members mounted on longitudinal endportions of said second roller.
 12. The medium discharging mechanismaccording to claim 1, wherein said second roller is one of a pluralityof second rollers that rotate about the rotating shaft (32 a), whereinsaid resiliently deformable member is disposed such that saidresiliently deformable member is sandwiched between adjacent secondrollers.
 13. The medium discharging mechanism according to claim 12,further comprising a weight member that is freely rotatable on therotating shaft and hangs down from the rotating shaft, wherein when themedium is pulled in between said first roller and said second roller,the leading end of the medium pushes the weight member out of the way sothat the weight member presses a surface of the medium until a trailingend of the medium leaves the nip.
 14. An image forming apparatusincorporating said medium discharging mechanism according to claim 1.15. The medium discharging mechanism according to claim 1, wherein saidfirst roller and second roller form a nip between them such that the niplies in a plane at an angle with a transport path in which the mediumadvances toward the nip.
 16. The medium discharging mechanism accordingto claim 15, wherein said first roller and said second roller arepositioned so that said first roller is on one side of the transportpath and said second roller is on the other side of the transport path,the first roller being upstream of said second roller with respect tothe transport path.
 17. An image forming apparatus incorporating saidmedium discharging mechanism according to claim 15.